Morphology of the male reproductive system and spermatophore of the red bollworm, Diparopsis castanea (Hmps.) and the possible effect of the chemosterilant tepa on the gross structure

The structure of the male reproductive system of the red bollworm, Diparopsis castanea (Hmps.), is described: it is typical for a Noctuid. After day-old male moths had been injected with dosages of the chemosterilant tepa ranging from 10 to 50 μg, no impairment of the gross function of their accessory gland apparatus resulted, and spermatophores of normal size were transmitted during copulation. Microscopic examination of testicular preparations demonstrated no gross damage following treatment, and the sperm was motile. The injected males were nevertheless completely sterile.     

Factors affecting the structure of substituted tris(pyrazolyl)borate rhodium dicarbonyl complexes

Predictions by density functional calculations of the structure and relative energy of various isomers of the hydridotris(pyrazol-1-yl)borate ligand in Tp^3R,5R rhodium(I) dicarbonyl complexes (R=H, Me) and their IR and ¹¹B NMR spectra are compared to experimental observations. The lowest energy structure of Tp^3,5-Me-, Tp^3-Me-, and TpRh(CO)₂ is a non-classical square pyramidal (SPy) structure with a long metal apical ligand distance in rapid exchange with an equivalent SPy structure through a low energy trigonal bipyramid (TBP) transition state (a ‘reverse’ Berry pseudorotation). A second higher energy minimum, a pseudo square-planar complex with the third uncoordinated pyrazolyl arm rotated approximately parallel with the metal ligand pseudo-plane (SP1), is accessed through a second low energy transition state. Another pseudo square-planar minimum structure (SP2) is produced by a transition state, which lengthens the rhodium-apical nitrogen (of the third pyrazolyl arm) bond distance. The relative stability of SP2 depends on the degree of tris(pyrazolyl)borate (Tp) substitution, where 5-substituents larger than hydrogen disfavor SP2 because of steric interactions. The previously reported empirical correlation between ¹¹B NMR chemical shifts, ν_BH stretching frequencies, and the crystallographic Tp ligand denticity is reproduced by our calculations. The variety of structures observed by experiment can be explained by the calculated relative energies of the structures, the bulk dielectric of the solvents when in solution, specific interaction by certain solvents, and conditions of crystallization when in the solid-state.     

Factors affecting the activity of alatae of the aphids Myzus persicae (Sulzer) and Brevicoryne brassicae (L.)

Apparatus was designed for testing the frequency of flights of aphids under different conditions of temperature, relative humidity, light and pressure. Young aphids (1–4 days after metamorphosis) flew more often and showed less individual variability than older ones; with all ages activity increased for the first few hours under experimental conditions. Starving increased activity for the first 1–2 hr. Aphids used in experiments on a second day flew less frequently than controls which had remained on the plant the first day. Alate B. brassicae were more active than M. persicae : both species showed alternating periods of activity and quiescence.
At light intensities between 100 and 1000 f.c. there was little difference in flight frequency, but below 100 f.c. activity declined rapidly and apparently ceased with darkness.
Changes in relative humidity temporarily affected flight frequency, a change to a higher humidity retarding, a change to a lower increasing it. After adjusting to the change aphids flew readily at all humidities tested between 50 and 100% with temperatures below 80° F. (26.7°C.). The combination of high humidity and high temperature (90°F. = 32·2°C.) sometimes inhibited flight.
Changes of pressure often increased activity temporarily and flight frequency was greater under fluctuating pressure than under constant pressure.
It is concluded that changes in microclimate in crops are adequate to influence frequency of flight of aphids and consequently the spread of virus diseases.     

Molecular mapping of a fertility restoration locus (Rfm1) for cytoplasmic male sterility in barley (Hordeum vulgare L.)

The Rfm1a gene restores the fertility of msm1 cytoplasmic male-sterile lines in barley. We identified three RAPD markers linked to the Rfm1 locus (CMNB-07/800, OPI-18/900, and OPT-02/700) using isogenic lines and segregating BC₁F₁ and F₂ populations. Using a previously developed linkage map of barley, we located CMNB-07/800 and OPT-02/700 beside MWG2218 on chromosome 6HS. The linkage between MWG2218 and the Rfm1 locus was demonstrated using the segregating BC₁F₁ and F₂ populations. To confirm the chromosomal locations of these markers, we converted them to STSs and tested against two sets of wheat–barley chromosome addition lines. These STS markers, CMNB-07/800, OPT-02/700, and MWG2218, were amplified only in the addition lines possessing the chromosome 6H, thereby providing additional evidence the Rfm1 locus is located on chromosome 6H. Homoeologous relationships among fertility restoration genes in Triticeae are discussed. Received: 27 March 2000 / Accepted: 25 June 2000     

Molecular mapping of two reverse photoperiod-sensitive genic male sterility genes (rpms1 and rpms2) in rice (Oryza sativa L.)

The reverse photoperiod-sensitive genic male sterility (PGMS) and thermo-sensitive genic male sterility (TGMS) lines have an opposite phenotype compared with normal PGMS and TGMS lines widely used by the two-line system in current hybrid rice seed production. Thus, the application of reverse PGMS and TGMS lines can compensate PGMS and TGMS lines in hybrid rice production. YiD1S is a reverse PGMS line, in which pollen fertility is mainly regulated by day-length, but also influenced by temperature. Genetic analysis indicated that male sterility of YiD1S was controlled by two recessive major genes. An F₂ population from a cross between YiD1S and 8528 was developed and used for molecular mapping of the two reverse PGMS genes which were first named rpms1 and rpms2. Both simple sequence repeat (SSR) markers and bulked segregant analysis (BSA) were used in this study. As a result, one reverse PGMS gene (rpms1) was mapped to the interval between SSR markers RM22980 (0.9 cM) and RM23017 (1.8 cM) on chromosome 8. Eight SSR markers, YDS818, RM22984, RM22986, RM22997, YDS816, RM23002, RM339 and YDS810 completely co-segregated with the rpms1 gene. Another reverse PGMS gene (rpms2) was mapped to the interval between SSR markers RM23898 (0.9 cM) and YDS926 (0.9 cM) on chromosome 9. The physical mapping information from publicly available resources shows that the rpms1 and rpms2 loci are located in a region of 998 and 68 kb, respectively. The analysis based on marker genotypes showed that the effect of rpms1 was slightly larger than that of rpms2 and that the two genes interacted in controlling male sterility. H. F. Peng, Z. F. Zhang and B. Wu contributed equally to this work.     

Factors affecting vesicle formation and acetylene reduction (nitrogenase activity) in Frankia sp. CpI1

Vesicle formation and acetylene reduction (nitrogenase activity) were observed when washed hyphae from cultures of Frankia sp. CpI1 were transferred to a nitrogen-free medium containing ethylenediaminetetraacetic acid and succinate. Succinate could be replaced by malate or fumarate, but not other carbon sources. Maximum acetylene reduction and vesicle numbers were observed at a pH of 6.0-6.5, at 25-30 degrees Centigrade, and at atmos pheric Po2 or somewhat less (5-20 kPa). Addition of 1 mM NH4Cl almost completely inhibited vesicle formation and acetylene-reducing activity, but did not immediately inhibit such reducing activity by cultures with preexisting vesicles. Acetylene-reducing activity was never observed in the absence of vesicle formation.     

Identification of mitochondrial genome rearrangements unique to novel cytoplasmic male sterility in radish (Raphanus sativus L.)

A novel cytoplasmic male-sterility (CMS) radish (Raphanus sativus L.) and its associated mitotype (DCGMS) were previously identified; however, no mtDNA fragments flanking the atp6 gene were found in the DCGMS mitotype. Unlike three other mitotypes in this study, a unique mtDNA organization, atp6–nad3–rps12, was found to be the major mtDNA structure associated with this mitotype. This organization may have arisen from short repeat sequence-mediated recombination events. The short repeat clusters involved in the mtDNA rearrangement around the atp6 gene also exist as repetitive sequences in the complete mitochondrial genomes of other members of the Brassicaceae family, including rapeseed and Arabidopsis. These sequences do not exist as repetitive elements in the mtDNA of tobacco, sugar beet, or rice. While studying the regions flanking atp6, we identified a truncated atp6 mtDNA fragment which consists of the 5′ part of the atp6 gene linked to an unidentified sequence. This mtDNA structure was present in all mitotypes; however, a single nucleotide insertion mutation leading to a frame-shift was identified only in the DCGMS mitotype. Although this truncated atp6 organization was transcribed, there was no significantly different expression between male-sterile and fertile segregating individuals from the BC₁F₁ population originating from a cross between male-sterile and restorer parents. Comprehensive survey of the single base-pair insertion showed that it was maternally inherited and unique to the DCGMS mitotype. Therefore, this single nucleotide polymorphism (SNP) in the coding sequence of the mtDNA will be a useful molecular marker for the detection of the DCGMS mitotype. Young-Pyo Lee and Sunggil Kim equally contributed to this work.     

Characterization and mapping of a novel mutant sms1 （senescence and male sterility 1） in rice

Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility (sms) was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild type control and was severe male sterile with lower pollen viability.Genetic analysis showed that the mutant was controlled by a single recessive gene.By the map-based cloning approach,we fine-mapped SMS1 to a 67 kb region between the markers Z3-4 and Z1-1 on chromosome 8 using 1,074 F2 recessive plants derived from the cross between the mutant sms1 (japonica) × Zhenshan 97 (indica),where no known gene involved in senescence or male sterility has been identified.Therefore the SMS1 gene will be a novel gene that regulates the two developmental processes.The further cloning and functional analysis of the SMS1 gene is under way.     

Characterization and mapping of a novel mutant sms1 (senescence and male sterility 1) in rice

Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility (sms) was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild t...     

Factors affecting the activity of two species of eel (Anguilla spp.) in a small New Zealand lake

Fyke net captures of both the shortfinned eel, Anguilla ausrralis Richardson, and the longfinned eel. A. dieffenbachü Gray, were recorded over a 4-year period in Lake Pounui. New Zealand. Eel activity measured as catch per unit effort (CPUE) was correlated to 36 indices of water temperature water level, barometric pressure, amount of light at night and lunar period using multiple regression analysis. For longfinned eels, water temperature was the only individual parameter significantly related (P<0.001) to CPUE. The multiple regression model was improved (R²= 0.29. P <0.01) by the addition of lunar phase and change in barometric pressure. Water level was the most important parameter in the model for shortfinned eels, although water temperature and change in barometric pressure were significant influences in the predictability of the model (R²= 0.51. P<0.001.     

Factors affecting the survival of ash (Fraxinus spp.) trees infested by emerald ash borer (Agrilus planipennis)

Emerald ash borer (Agrilus planipennis) (EAB), an Asian woodboring beetle accidentally introduced in North America, has killed millions of ash (Fraxinus spp.) trees and is spreading rapidly. This study examined the effects of tree- and site-level factors on the mortality of ash trees in stands infested by EAB in OH, USA. Our data show that ash populations in forested sites can progress from healthy to almost complete mortality of mature trees within 6 years. Although the end result of nearly complete mortality does not vary, survival analysis with 5 years of data showed that some factors affected the rate of mortality. We found more rapid mortality in stands with lower densities of ash trees. This finding supports an extension of the resource dilution hypothesis whereby concentration of EAB on few trees in low ash density areas leads to rapid decline of these trees. This contradicts an extension of the resource concentration theory that greater host density increases relative pest abundance and host mortality. Although reductions in ash density via diversification may be desirable for other silvicultural, conservation, and management objectives in preparation for EAB, our study shows that the management strategy of reducing ash density is unlikely to protect the remaining ash trees. Survival analysis also showed that mortality was more rapid for trees shaded by other trees and for trees initially exhibiting dieback. In management scenarios where hazard tree removal must be spread over several years due to budget constraints, focusing initial tree removal on stressed trees is recommended.     

Factors affecting the seasonal distribution of red deer (Cervus elaphus) at Glen Dye, north-east Scotland

Part of a red deer herd found on an estate in north-east Scotland in summer spent more time on neighbouring ground during the winter where they damaged farms and woods. Factors associated with the deer's seasonal distribution were studied to help understand how to keep more deer on the estate in winter. There were no indications that food species or food quality were responsible for the observed changes in deer distribution, or that other animals or disturbance influenced distribution over a long period. Deer sought shelter from chilling winds, and areas occupied by deer in winter had more sheltered ground from wind, and the quality of this shelter was higher than on the areas little used. Home-range behaviour and tradition appeared to determine which areas particular deer occupied in winter. The main recommendation for management was to re-open mature woodland to provide more and better shelter on the estate in order to get more control over the deer stock and to reduce marauding.     

Ecological and genetic factors contributing to the low frequency of male sterility in Chamaecrista Fasciculata (Fabaceae)

Bumble bee pollinated Chamaecrista fasciculata provides pollen as the sole reward to its pollinators. Male sterility, expressed as an absence or nearly complete absence of pollen production, occurs in low frequency in populations of C. fasciculata. Here we describe experiments, using C. fasciculata, to examine frequently cited determinants of the spread and maintenance of male sterility: compensation and the genetic basis of male sterility. In addition, we examine the role the pollination system plays in determining the reproductive success of the male steriles. Seventeen populations in Maryland, Illinois, and Kansas were surveyed and found to range from 0 to 6% male sterility per population. An artificial population of male-sterile simulants and hermaphrodites was created to examine how the local frequency of nonrewarding male steriles might affect male-sterile female reproductive success. Male steriles performed equally poorly, with respect to seed production, whether surrounded by other male-sterile simulants or hermaphrodites. Compensation was examined by comparison of male steriles and hermaphrodites with respect to several reproductive and nonreproductive characters. Male steriles outperformed hermaphrodites in terms of nonreproductive biomass, but performed equally in terms of ovule number and produced many fewer flowers. The genetic basis of male sterility was examined by performing both intra- and interpopulational crosses of male steriles to hermaphrodites and indicate that male sterility is not purely cytoplasmic. The low frequency of male sterility in C. fasciculata populations may reflect reduced female reproductive success because of pollinator avoidance, lack of reproductive compensation, and a mode of inheritance that is not purely cytoplasmic.     

Factors affecting the fermentation of ergot alkaloids by Aspergillus fumigatus (Fresenius)

Summary Six strains of Aspergillus fumigatus were studied for their alkaloid producing capacity. With one strain (NCIM 902) high yields (162mg/l) of ergot alkaloids were obtained after seven days in a new medium.     

The nest-holding grass goby (Zosterisessor ophiocephalus) male adjusts the spawning activity in relation to parasitic nest intrusions

This study examines the temporal pattern of spawning behavior by the territorial (i.e. nest-holding) grass goby male, Zosterisessor ophiocephalus, in response to sneak intrusions by the small parasitic male under controlled laboratory conditions. The spawning activity of the territorial male consists of a sequence of upside–down movements on the ceiling of the nest accompanied by undulations of the body and sperm release. Five pairs of one territorial male and one parasitic male, each kept inside a large tank provided with an artificial buried nest (always occupied by the territorial male) and one small tunnel-shaped shelter (always occupied by the small male), were observed during one-female spawning taking place in the innermost part of the nest (i.e. the nest chamber). During the spawning, the presence of the small male nearby the nest openings elicited aggressive behavior and increased nest patrolling by the territorial male. In one spawn the small male never attempted to enter the nest. In four spawns the small male entered one to three times the nest chamber (sneaks), staying there from 2 to 203 s until the large male chased him away. The temporal patterning of the spawning activity by the territorial male (bouts of upside–down, U–D), and its changes following a sneak by the small male, were investigated using bout analysis and correlative tests. Results showed the length of bouts U–D did not change significantly after a sneak intrusion. whereas gap length (i.e. the period between subsequent bouts U–D) decreased significantly after each sneak intrusion. The mean duty cycle of bouts U–D tended to be positively correlated to the number of sneaker intrusions of each replicate. Results are discussed in the light of current knowledge on sperm competition among externally fertilizing teleosts.     

Factors affecting the development of cane blight (Leptosphaeria coniothyrium) on red raspberries in Washington, Scotland and Germany

The effects of cultivar, virulence of isolates of Leptosphaeria coniothyrium, cane maturation and wound healing were examined in a series of inoculation experiments carried out over a 3–yr period in three countries in an attempt to explain why cane blight has caused serious yield losses in machine-harvested red raspberries in Europe, but not in the Pacific Northwest of America. Three isolates of L. coniothyrium from Puyallup (USA), Dundee (UK) and Dossenheim (FRG) were pathogenic on the three test cultivars Willamette, Malling Jewel and Glen Isla in all the experiments. Isolates and cultivars differed for aggressiveness and susceptibility respectively but their ranking was dependent on the test conditions and the differences were small and unlikely to explain the differences in incidence and severity of cane blight in raspberry fields in Scotland and the Pacific Northwest. Conditions at Dossenheim were most favorable for lesion development. At all sites, canes inoculated in late summer produced shorter lesions than those inoculated earlier. A delay between wounding and inoculation produced shorter lesions than simultaneous wounding and inoculation.